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開水路粗度急変部における流れの遷移と流砂機構に関する研究

明渠粗糙度变化过程中水流转变及输沙机制研究

基本信息

批准号：
02650359
负责人：
MURAMOTO Yoshio
金额：
$ 1.34万
依托单位：
KYOTO UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1990
资助国家：
日本
起止时间：
1990 至 1991
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-02650359/
关键词：
sudden change in roughness bed protection work revetment local scour bed evolution field observation spot roughness trapezoidal channel 非平衡流砂

项目摘要

1. Experiments of local scour in downstream reaches of various types of bed protection works including smooth fixed bed were carried out under dynamical equilibrium conditions of bed load. Variations of scour holes profiles and their maximum depths with time were discussed on three types of bed protection works, and compared with those under a static equilibrium condition. Flow characteristics, such as, velocity distributions, bed shear stress and pressure on the scoured bed were also measured at several stages of scour process. The scour processes could be simulated by the case of bed shear stress distributions measured along the maximum scour profile and non-equilibrium bed load functions, especially in the early stage of the scour.2. Field measurement of scour profiles were carried out at a downstream reach of hollow-squared blocks in the Manganji River in Hyogo prefecture, and the observed scour profiles and velocity distributions proved to be similar to those measured in the experiments.3. Water surface profiles and turbulent structures of open channel flows produced by sudden change in side-wall roughness from smooth to rough were discussed experimentally. The transition of flow was found to mainly depend on the bed slope and classified into three patterns. In the downstream reach after the roughness change, distributions of the velocity and turbulence property vary with development of the internal boundary layer similar to those by sudden change in bottom roughness.

1. 在床荷载动态平衡条件下，对包括光滑固定床在内的各类护坡工程下游河段进行了局部冲刷试验。讨论了三种护坡工程冲刷孔剖面及其最大深度随时间的变化规律，并与静力平衡条件下的冲刷孔剖面及最大深度进行了比较。在冲刷过程的各个阶段，测量了冲刷床上的流速分布、床层剪应力和压力等流动特性。冲刷过程可以通过沿最大冲刷剖面和非平衡层载函数测量的床层剪应力分布来模拟，特别是在冲刷的早期阶段。2 .对兵库县满干济河下游一段空心方块河道进行了冲蚀剖面实测，实测冲蚀剖面和流速分布与实验结果基本一致。实验研究了明渠边壁粗糙度由光滑变为粗糙所产生的水面剖面和湍流结构。发现水流的过渡主要取决于河床坡度，并分为三种模式。在粗糙度变化后的下游河段，速度和湍流性的分布随内边界层的发展而变化，类似于底部粗糙度突变时的分布。